In the field of torches and lamps, LED has been used as the light emitter for less electricity and high illuminative performance. A torch usually set a lens in front of a LED to focus the light beam in a narrow included angle for an enhance light spot. In the prior art, the lens was movable in forward-backward to the light emitter for casting the light beam to shine a zoom-able spot. The mechanical method of changing distance of the focus distance of a lens usually set the lens on a sleeve with a screwing thread and screwed the sleeve to main body of the torch. By the screwing the sleeve, the distance between the lens and the led would be changed. Therefore, each time the regulation of zoom in or out of the light spot needed to use both hand to screw the sleeve out or in.
In prior art, a LED circuit board was set by an elastic element to against and holding on front of the main body. As the elastic element fatiguing, the conduction of the circuit board and the batteries would fail. The material of the torch with bed cooling efficiency of the main body caused the LED circuit board too hot and shortened the life of LED.
Accordingly, in view of the foregoing, there is currently a need in the art for improving devices on the regulation of the focus distance of the lens for casting a zoom-able spot by one hand, and the methods of sealing LED circuit board.